<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        *{
            margin: 0;
            padding: 0;
            list-style:none;
        }
        body{
            background-color: #eee;
            font-family: "Microsoft Yahei";

        }
        section{
            width: 1000px;
            margin:50px auto;
        }
        section h3{
            font-size:22px;
            font-weight: normal;
        }

        ul{
            border: 1px solid #999;
            background-color: #fff;
            display: flex;

        }

        ul li{
            width: 200px;
            height: 200px;
            background: pink;
            margin:10px;

        }

        section:nth-child(1) ul li:nth-child(1){
            flex:1;
        }

        section:nth-child(1) ul li:nth-child(2){
            flex:1;
        }

        section:nth-child(1) ul li:nth-child(3){
            flex:8;
        }

        section:nth-child(2) ul li:nth-child(1){

        }

        section:nth-child(2) ul li:nth-child(2){
            flex:1;
        }

        section:nth-child(2) ul li:nth-child(3){
            flex:4;
        }


    </style>
</head>
<body>
<section>
    <h3>伸缩比例:flex</h3>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
    </ul>
</section>

<section>
    <h3>伸缩比例:flex</h3>
    <ul>
        <li>1</li>
        <li>2</li>
        <li>3</li>
    </ul>
</section>


</body>
</html>